A spectator at the Africville Museum Baptist church grounds takes a photo of the Bedford Basin as the float test for the Future HMCS Harry DeWolf gets underway Saturday afternoon. - Eric Wynne

A delicate ballet of steel and water played out on Halifax Harbour over the weekend, as the first Arctic Offshore Patrol Vessel, the Future HMCS Harry DeWolf entered the water for the first time. The launch was significant for a number of reasons. The launch of AOPS1 — the name the DeWolf will carry until it is commissioned — was the first to take place at the Halifax Shipyard since it was rebuilt. AOPS1 is also not just the first in a new class of ship, but the first of a new type of vessel, not operated by the navy in more than 50 years. This is also the first launch to take place away from the shipyard.

When the fog cleared mid-morning Saturday, the future HMCS Harry DeWolf sat on a barge in the Bedford Basin, surrounded by support vessels and curious onlookers both on land and at sea. From Seaview park to the China Town Restaurant, parking lots were full of people with cameras and binoculars. They were about to see something different.

Where previously the newly finished vessel would seem to slide down the now-retired launching ways into the water with splash, this would be a slower and more involved endeavor.

Since its formation as Halifax shipyard in 1918, the shipyard had launched 102 vessels from a traditional launching way at the south end of the yard. Newly built ships would slide stern first down a gentle slope on a cradle and into the water, floating free once the hull’s buoyancy took effect. The last vessel to be launched this way was the Coast Guard mid-shore patrol vessel CCGS Captain Goddard M.S.M. in 2014. It went into the water as the old assembly hall was being taken down behind it to make room for the shipyard modernization.

The launch of AOPS1 was actually a three-day process.

It began Thursday, when the huge Boa Barge 37 was moved into place off Pier 8, where the new navy vessel has spent the last year after the three mega blocks that make it up were rolled out of the assembly hall and joined. A ship under construction is always difficult to name. Until it’s commissioned into the navy, it’s known as the Future HMCS Harry DeWolf or by its class and hull number, AOPS1.

On Friday morning, AOPS1 was loaded aboard the semi-submersible barge, which is partially sunk to allow vessels to float on and off of it. Semi-submersible vessels often bring drill rigs, or other vessels into and out of Halifax harbor. In all, it took four hours to move AOPS1 its own length backwards onto the barge.

Loading a 6,615-tonne ship onto a floating platform in tidal waters is a delicate process. Not only does the barge need to be ballasted properly to sit level with the pier and allow a smooth transfer, both the tide and the uneven loading of the barge caused by the ship being moved onto it requires water to be very carefully pumped around the Boa Barge 37’s 26 tanks to keep the barge properly oriented. Mistakes with ballast control could have caused the ship to topple into the water, or even for the barge to sink. This first step of the launching was complete by 1 p.m. Friday, leaving the rest of the day for other preparations.

The launching itself began at 4:30 a.m. Saturday, with Atlantic Towing's tugs Atlantic Oak, Atlantic Bear, and Spitfire III moving the Boa Barge 37 to the basin. The barge left the shipyard around 7:30 a.m. and under cover of thick fog reached the launching location in the basin just over an hour later.

The launching location has a water depth of just over nearly 30 metres, leaving enough room for the barge to sink itself and allow AOPS1 to float free. Over the course of the day, the barge slowly sunk, with the new vessel afloat just before 5 p.m.

The next step was a tow back to the shipyard.

Semi-submersible operations are slow but also potentially risky. The Halifax Shipyards own Scotia Dock II sank while it was submerging to dock the tug Stevens Breaker in 2010, and spent several months on the bottom before it was successfully raised. The Scotia Dock II was eventually declared a loss and sold for scrap.

The Boa Barge 37 was refloated overnight Saturday, and was due to move back to the shipyard Sunday.

Within the next few weeks, the second Arctic Offshore Patrol Ship, to be named HMCS Margaret Brooke, will take its final form, as the three mega blocks that make it up are rolled out onto Pier 8 and joined. If timelines go as planned, we should see the second launching in June of next year.